Device for reducing chemical oxygen demand in mother liquor of evaporative crystallization system
By using sodium hypochlorite to oxidize and decompose organic matter in the mother liquor in the evaporation crystallization system, the problem of increased COD content in the mother liquor is solved, the operation cycle is improved and the operation cost is reduced, and a virtuous cycle is achieved.
Patent Information
- Application Number
- CN202323588119.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2033-12-27
AI Technical Summary
The chemical oxygen demand (COD) in the mother liquor in the evaporation crystallization system increases with the increase of the operating cycle, resulting in a decrease in the system's evaporation and operation efficiency, forming a vicious cycle. It is difficult for the prior art to effectively reduce the COD content in the mother liquor.
Install mixing parts in the mother liquor tank, and install sodium hypochlorite solution in the sodium hypochlorite tank. The sodium hypochlorite solution is passed into the mixing parts through the connecting pipes, and the organic matter in the mother liquor is oxidized and decomposed by sodium hypochlorite to reduce the COD content.
Effectively remove COD in mother liquor, extend the operating cycle, reduce production costs, avoid the impact on subsequent production, and form a virtuous cycle.
Smart Images
Figure CN222138825U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of evaporation crystallization equipment, in particular to a device for reducing the chemical oxygen demand in the mother liquor of an evaporation crystallization system. Background Art
[0002] The use of evaporation and crystallization technology is the current trend in the treatment of high-salt wastewater. Under the evaporation and crystallization method, most of the water and low-boiling-point organic matter in the sewage are vaporized under heating conditions, and the concentration of salt and high-boiling-point organic matter in the remaining sewage gradually increases. After reaching the saturation concentration, the salt precipitates and the salt and water are separated, thereby avoiding the impact of salinity in most wastewater on the biochemistry of the sewage; Chemical Oxygen Demand (COD) is a chemical method that measures the amount of reducing substances that need to be oxidized in the water sample. The oxygen equivalent of substances (generally organic matter) that can be oxidized by strong oxidants in wastewater, effluent from wastewater treatment plants and contaminated water is an important and quickly measured organic pollution parameter in the study of river pollution and industrial wastewater properties and the operation and management of wastewater treatment plants. It is often represented by the symbol COD. The evaporation crystallization process is suitable for processes with low COD values. Its main purpose is to separate the solid and liquid of high-salt wastewater, and it is necessary to consider the regular discharge of high-boiling-point organic matter. The mother liquor is the saturated solution remaining after the precipitate or crystal is separated in the chemical precipitation or crystallization process. In order to ensure the efficient operation of the evaporation crystallization device, the concentrated mother liquor needs to be discharged and treated regularly. The mother liquor is the saturated solution remaining after the precipitate or crystal is separated in the crystallization process. When the impurity content (COD) in the mother liquor reaches a certain value (when the boiling point of the material rises by more than 9°C), the evaporation effect of the system is reduced, and the brine treatment capacity of the device cannot reach the operation target.
[0003] Evaporation, concentration and crystallization is a chemical unit operation method. It uses heating to evaporate part of the solvent so that the salt in the wastewater can be precipitated, which can effectively remove the salt in the wastewater. At the same time, due to the presence of high COD in the wastewater, during the evaporation of the solvent, the water and organic matter are separated by using the different boiling points of organic matter and water. It is mainly designed based on the principle that water has different boiling temperatures at different pressures. There are also advanced treatment technologies such as membrane separation and ion exchange for high-salt and high-COD wastewater. However, with the complexity of the composition of high-salt and high-COD wastewater and the severity of the sewage treatment situation, a single treatment technology can no longer meet the high requirements of wastewater treatment. The optimization and integration of multiple advanced treatment technologies has become the development trend of wastewater treatment. The selection of wastewater treatment technology is based on two principles. One is the effective removal of salinity and COD, and the other is the cost of wastewater treatment technology. For example, the integration of distillation and biochemical methods, for high-salinity biodegradable wastewater, the wastewater is first pretreated using an evaporation, concentration, and crystallization process to reduce the concentration of soluble inorganic salt ions in the wastewater. The pretreated wastewater is then subjected to a suitable activated sludge method for COD removal based on its biodegradability.
[0004] However, the existing evaporation and crystallization system can only allow the mother liquor to enter the system circulation for treatment. As the operating cycle of the evaporation and crystallization system increases, the amount of mother liquor in the system will gradually increase. The enrichment of impurities causes the MVR evaporation boiling point to increase or the heat exchange efficiency to seriously decrease, resulting in a decrease in the system's evaporation capacity and operating efficiency. In order to ensure smooth production operation and extend the operating cycle, the crystallization separator will be drained and replaced, and diluted with unsaturated brine to ensure the normal operation of the system. The liquid is discharged to the accident brine tank and eventually returned to the three waste systems, affecting the salt content of the three waste systems and forming a vicious circle. Utility Model Content
[0005] In view of this, an embodiment of the utility model provides a device for reducing the chemical oxygen demand in the mother liquor of the evaporation crystallization system. The main purpose is to provide a device that can effectively reduce the chemical oxygen demand in the concentrated mother liquor produced by the evaporation crystallization system.
[0006] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:
[0007] The present invention provides a device for reducing the chemical oxygen demand in the mother liquor of an evaporation crystallization system, the device comprising:
[0008] An evaporation component, the evaporation component comprising a separator, a thickener, a centrifuge and a mother liquid tank, the separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquid tank is connected to the thickener and the centrifuge respectively;
[0009] The decomposition component comprises a sodium hypochlorite tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component, and both ends of the delivery pump are respectively connected to the mother liquid tank and the mixing component.
[0010] Furthermore, the mixing component includes a mixing tank, a stirring shaft, a stirring blade and a stirring motor, one end of the stirring shaft is connected to the stirring motor, and the other end extends into the mixing tank, and the stirring blade is installed on the side of the stirring shaft.
[0011] Furthermore, the mixing tank is a fiberglass reinforced plastic mixing tank.
[0012] Furthermore, the mixing component further comprises a feed valve, and the feed valve is arranged on the connecting pipe.
[0013] Furthermore, the horizontal position of the sodium hypochlorite tank is higher than the horizontal position of the mixing component.
[0014] Furthermore, a recovery system is provided, wherein the recovery system is connected to the mixing component.
[0015] Furthermore, the recovery system includes a recovery pipeline, a recovery valve and a three-waste treatment unit. The recovery pipeline is arranged between the three-waste treatment unit and the mixing tank, and the recovery valve is arranged on the recovery pipeline.
[0016] Furthermore, the evaporation component further includes a discharge pump, and the discharge pump is arranged between the separator and the thickener.
[0017] Compared with the prior art, the utility model has the following technical effects:
[0018] In the technical solution provided by the embodiment of the utility model, the function of the evaporation component is to collect the mother liquor, the evaporation component includes a separator, a thickener, a centrifuge and a mother liquor tank, the separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquor tank is respectively connected to the thickener and the centrifuge; the function of the decomposition component is to reduce the COD content in the mother liquor, the decomposition component includes a sodium hypochlorite tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component, and the two ends of the delivery pump are respectively connected to the mother liquor tank and the mixing component. Compared with the prior art, the evaporation crystallization system can only allow the mother liquor to enter the system circulation for treatment. As the operation cycle of the evaporation crystallization system increases, the amount of mother liquor in the system will gradually increase. The enrichment of impurities causes the MVR evaporation boiling point to increase or the heat exchange efficiency to seriously decrease, resulting in the system evaporation amount and operation efficiency. The rate is reduced. In order to ensure stable production operation and extend the operation cycle, the crystallizer will be drained and replaced, and diluted with unsaturated brine to ensure the normal operation of the system. The liquid is discharged to the accident brine tank and finally returned to the three waste systems, affecting the salt content of the three waste systems and forming a vicious circle. In the technical scheme, a mixing component is installed on the mother liquor tank, and then a sodium hypochlorite solution is configured in the sodium hypochlorite tank, and then the sodium hypochlorite solution is passed into the mixing component through a connecting pipe. The delivery pump passes the mother liquor in the mother liquor tank into the mixing component, so that the organic matter in the mother liquor is oxidized and decomposed into small molecules by sodium hypochlorite. Adding sodium hypochlorite to the mother liquor will not affect the subsequent production, nor will it introduce other impurities. It can not only effectively remove the COD content in the mother liquor, so that the subsequent processes can form a virtuous cycle and improve the operation cycle, but also reduce the operating cost in the production process, thereby achieving the technical effect of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of the structure of a device for reducing the chemical oxygen demand in the mother liquor of an evaporation crystallization system provided by an embodiment of the utility model;
[0020] Figure 2 A schematic structural diagram of a mixing component provided in an embodiment of the utility model. DETAILED DESCRIPTION
[0021] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0022] like Figure 1 and Figure 2 As shown, the embodiment of the utility model provides a device for reducing the chemical oxygen demand in the mother liquor of the evaporation crystallization system, the device comprising:
[0023] An evaporation component, the evaporation component includes a separator, a thickener, a centrifuge and a mother liquid tank, the separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquid tank is connected to the thickener and the centrifuge respectively;
[0024] The decomposition component comprises a sodium hypochlorite tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component, and both ends of the delivery pump are respectively connected to the mother liquid tank and the mixing component.
[0025] In the technical solution provided by the embodiment of the utility model, the function of the evaporation component is to collect the mother liquor, the evaporation component includes a separator, a thickener, a centrifuge and a mother liquor tank, the separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquor tank is respectively connected to the thickener and the centrifuge; the function of the decomposition component is to reduce the COD content in the mother liquor, the decomposition component includes a sodium hypochlorite tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component, and the two ends of the delivery pump are respectively connected to the mother liquor tank and the mixing component. Compared with the prior art, the evaporation crystallization system can only allow the mother liquor to enter the system circulation for treatment. As the operation cycle of the evaporation crystallization system increases, the amount of mother liquor in the system will gradually increase. The enrichment of impurities causes the MVR evaporation boiling point to increase or the heat exchange efficiency to seriously decrease, resulting in a decrease in the system evaporation amount and operation efficiency. In order to ensure production In order to ensure smooth operation and extend the operation cycle, the crystallizer separator will be replaced by drainage and diluted with unsaturated brine to ensure the normal operation of the system. The liquid is discharged to the accident brine tank and finally returned to the three waste systems, affecting the salt content of the three waste systems and forming a vicious circle. In the technical scheme, a mixing component is installed on the mother liquor tank, and then a sodium hypochlorite solution is configured in the sodium hypochlorite tank, and then the sodium hypochlorite solution is passed into the mixing component through a connecting pipe. The delivery pump passes the mother liquor in the mother liquor tank into the mixing component, so that the organic matter in the mother liquor is oxidized and decomposed into small molecules by sodium hypochlorite. Adding sodium hypochlorite to the mother liquor will not affect the subsequent production, nor will it introduce other impurities. It can not only effectively remove the COD content in the mother liquor, so that the subsequent processes can form a virtuous cycle and improve the operation cycle, but also reduce the operating cost in the production process, thereby achieving the technical effect of reducing costs and increasing efficiency.
[0026] The function of the above-mentioned evaporation component is to collect the mother liquor. The evaporation component includes a separator, a thickener, a centrifuge and a mother liquor tank. The separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquor tank is connected to the thickener and the centrifuge respectively. The concentrated liquid at the bottom of the separator in the evaporation crystallization system is transported to the thickener for solid-liquid separation, and the upper concentrated liquid enters the mother liquor tank. The concentrated liquid separated by the centrifuge from the material at the bottom of the thickener also enters the mother liquor tank, thereby achieving the technical effect of separating the concentrated liquid. Optionally, the evaporation component also includes a discharge pump, which is arranged between the separator and the thickener, and can quickly discharge the concentrated liquid at the bottom of the separator and transport it to the thickener; the function of the decomposition component is to reduce the COD content in the mother liquor. The decomposition component includes a secondary A sodium chlorate tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component. Both ends of the delivery pump are connected to the mother liquid tank and the mixing component respectively. A sodium hypochlorite solution is arranged in the sodium hypochlorite tank, and then the sodium hypochlorite solution is delivered to the mixing component. The horizontal position of the sodium hypochlorite tank is higher than the horizontal position of the mixing component, so that the sodium hypochlorite solution can flow into the mixing component. The delivery pump delivers the concentrated liquid in the mother liquid tank to the mixing component, so that the free chlorine in the sodium hypochlorite solution reacts with the organic matter in the concentrated liquid and is oxidized and decomposed into small molecules. The oxidizing property of the sodium hypochlorite aqueous solution is achieved by the hypochlorous acid generated by hydrolysis. After the hypochlorous acid oxidizes the organic matter, it becomes chloride ions and water. The specific reaction formula is:
[0027] NaClo+macromolecule organic matter→NaCl+H2O+small molecule organic matter / (CO2↑+H2O);
[0028] Adding sodium hypochlorite to the mother liquor will not affect subsequent production, nor will it introduce other impurities. It can not only effectively remove the COD content in the mother liquor, allowing subsequent processes to form a virtuous cycle and improve the operating cycle, but also reduce operating costs in the production process, thereby achieving the technical effect of reducing costs and increasing efficiency.
[0029] The specific experimental data are as follows:
[0030] The evaporation crystallization device processes about 8 cubic meters of mother liquor every day. The mother liquor enters the glass fiber reinforced plastic stirring tank, and 15 kg of sodium hypochlorite (10%) is added. After sufficient stirring and reaction, a comparison sample before and after the addition of sodium hypochlorite is obtained through chemical analysis;
[0031] Similarly, 8 cubic meters of mother liquor was added to the glass fiber reinforced plastic mixing tank, and 30 kg and 45 kg of sodium hypochlorite (10%) were added, and the mixture was stirred and reacted fully. Then, the comparison samples before and after the addition of sodium hypochlorite were obtained through chemical analysis. The analysis results are shown in Table 1:
[0032]
[0033] Table 1
[0034] The laboratory's comparative test results of hydrogen peroxide and sodium hypochlorite are shown in Table 2:
[0035]
[0036] Table 2
[0037] Hydrogen peroxide was added to the mother liquor, and the experimental data are shown in Table 3:
[0038]
[0039]
[0040] Table 3
[0041] Through the above analysis results, it can be seen that adding 10ml of sodium hypochlorite (10%) to 2000ml of mother liquor has the best effect. After the addition of hydrogen peroxide, the reducing substances that may exist in the mother liquor undergo a redox reaction with hydrogen peroxide, resulting in an increase in COD. Therefore, compared with the strong oxidant hydrogen peroxide and sodium hypochlorite, sodium hypochlorite is the most suitable reagent. At the same time, by comparing the removal results of the large-scale on-site system data, it is finally concluded that the optimal usage is 44kg of sodium hypochlorite (10%) for daily treatment of 8m3 of mother liquor. In the end, the COD in the mother liquor can be completely removed. Therefore, it can be determined that this method is feasible and can achieve the ideal effect of operation.
[0042] Furthermore, the mixing component includes a mixing tank, a stirring shaft, a stirring blade and a stirring motor, one end of the stirring shaft is connected to the stirring motor, the other end extends into the mixing tank, and the stirring blade is installed on the side of the stirring shaft. In this embodiment, the mixing component is further defined, the mixing tank is a glass fiber reinforced plastic mixing tank, specifically, the mixing tank is made of glass fiber reinforced plastic material, the stirring shaft and the stirring blade are made of carbon steel, the surface anti-corrosion material is epoxy furan resin, the stirring shaft is installed on the stirring motor, and the stirring blade is installed on the side of the stirring shaft, and the stirring motor drives the stirring shaft and the stirring blade to rotate, so that the sodium hypochlorite solution and the concentrated solution are fully mixed and reacted, thereby achieving the technical effect of improving the reaction efficiency.
[0043] Furthermore, the mixing component further includes a feed valve and a liquid level meter, the feed valve is arranged on the connecting pipe, and the liquid level meter is arranged on the side of the mixing tank. In this embodiment, the mixing component is further defined, the feed valve is arranged on the connecting pipe, and when the connecting pipe needs to be opened, the feed valve is opened, and the sodium hypochlorite solution enters the mixing tank from the connecting pipe. At the same time, a liquid level meter is arranged on the side of the mixing tank for real-time monitoring of the liquid level in the mixing tank.
[0044] Further, a recovery system is connected to the mixing component. In this embodiment, a recovery system is added, and the function of the recovery system is to recover and treat the waste liquid after the reaction, and the content of organic matter and COD in the waste liquid after the reaction is reduced, and then enter the recovery system for centralized treatment. Specifically, the recovery system includes a recovery pipeline, a recovery valve and a three-waste treatment unit. The recovery pipeline is arranged between the three-waste treatment unit and the mixing tank, and the recovery valve is arranged on the recovery pipeline. The waste liquid is discharged from the bottom of the mixing tank and enters the three-waste treatment unit from the recovery pipeline for centralized treatment. The recovery valve controls the opening or closing of the recovery pipeline, so as to achieve the technical effect of quickly discharging the waste liquid.
[0045] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.
Claims
1. A device for reducing the chemical oxygen demand in the mother liquor of an evaporative crystallization system, It is characterized in that include: An evaporation component, the evaporation component comprising a separator, a thickener, a centrifuge and a mother liquid tank, the separator is connected to the thickener, the centrifuge is connected to the bottom of the thickener, and the mother liquid tank is connected to the thickener and the centrifuge respectively; The decomposition component comprises a sodium hypochlorite tank, a connecting pipe, a mixing component and a delivery pump, one end of the connecting pipe is connected to the sodium hypochlorite tank, and the other end is connected to the mixing component, and both ends of the delivery pump are respectively connected to the mother liquid tank and the mixing component.
2. The device according to claim 1, It is characterized in that The mixing component comprises a mixing tank, a stirring shaft, a stirring blade and a stirring motor. One end of the stirring shaft is connected to the stirring motor, and the other end extends into the mixing tank. The stirring blade is installed on the side of the stirring shaft.
3. The device according to claim 2, It is characterized in that The mixing tank is a glass fiber reinforced plastic mixing tank.
4. The device according to claim 2, It is characterized in that The mixing component further comprises a feed valve, which is arranged on the connecting pipe.
5. The device according to claim 2, It is characterized in that The horizontal position of the sodium hypochlorite tank is higher than the horizontal position of the mixing component.
6. The device according to any one of claims 2 to 5, It is characterized in that Also includes: A recovery system is connected to the mixing component.
7. The device according to claim 6, It is characterized in that The recovery system comprises a recovery pipeline, a recovery valve and a three-waste treatment unit. The recovery pipeline is arranged between the three-waste treatment unit and the mixing tank, and the recovery valve is arranged on the recovery pipeline.
8. The device according to any one of claims 1 to 5, It is characterized in that The evaporation component further includes a discharge pump, and the discharge pump is arranged between the separator and the thickener.